A Striped Dolphin caught in a driftnet in the Northeast Atlantic Ocean.

Earth Talk

Destructive Driftnet Fishing

From the Editors of E/The Environmental Magazine

Dear EarthTalk:Is it true that some commercial fishing nets are
40 miles long? I heard a TV commentator accuse fishing fleets of "strip-mining
the oceans." If their nets are really that large, it certainly sounds like
that's what is happening!

-- B. Johnson, Port Chester, NY

Considered the most destructive fishing technology ever devised, commercial
"drift netting" involves vertically suspending near-transparent nylon
nets in ocean waters with floats attached to the top and weights fixed to the
bottom. Some are known to be as much as 50 miles wide, with a vertical height
of about 50 feet deep.

Once set, the nets are allowed to drift with the wind and currents (hence the
term "drift net") and to snag just about everything in their paths.
Drift netting is considered to be the most efficient way to catch large amounts
of the ocean's biggest fish, including tuna, swordfish, marlin and salmon.

The problem with these gigantic nets is that they don't discriminate between
fish that can be sold for dinner tables and so-called "by-catch"--marine
life not intended for food but which get hauled up anyway and then subsequently
discarded dead back into the ocean. Drift netting is responsible not only for
killing fish that will never be sold commercially, but also for the unnecessary
death of hundreds of thousands of dolphins, seals, whales and sea turtles every
year, despite international agreements outlawing the practice.

Driftnets also sometimes break loose, sailing through the oceans unattended,
"ghost fishing" until they sink to the bottom under the weight of
their victims or wash up onshore where they snag seabirds, seals and other
unsuspecting wildlife.

First developed by Japan in the 1970s, drift netting quickly caught on elsewhere
and within just a decade scientists began to notice that the practice was taking
a severe toll on marine biodiversity.

Various experiments were conducted that bore out these concerns. A 1989 test
using driftnets to catch tuna, for example, killed an average of four and a half
marine mammals in every "set"--one whale or dolphin for every 10 tuna
caught. Meanwhile, analysts observed a Japanese boat kill 59 dolphins and small
whales in just 30 sets--a rate of almost two per set.

With commercial fishing fleets legally deploying some 30,000 miles of driftnets
around the world daily during the 1980s, the toll on marine life was no doubt
staggering.

The first major effort to stop drift netting was the Wellington Convention, which
was signed in New Zealand in 1989 and put into place a driftnet ban in the South
Pacific. Four years later, the United Nations called for an international moratorium
on the practice.

Meanwhile, in 1992 Russia, Japan and the United States created the Convention for
the Conservation of Anadromous Stocks in the North Pacific, banning all driftnets
more than 1 1/2 miles in length ("anadromous" refers to fish like salmon
that live in salt water but spawn in fresh water). South Korea signed on but China
did not, though it agreed to let the U.S. Coast Guard help police its fleet. In
2002, the European Union banned drift netting by its member countries.

According to Earthtrust, a U.S. nonprofit committed to ending drift netting,
despite such commitments commercial fishing fleets around the world still deploy
tens of thousands of miles of driftnets on a daily basis. While efforts to stop
the practice have no doubt had some effect, drift netting remains one of the
biggest drivers of over-fishing today. As long as demand for tuna, salmon and
other big fish continues, drift netting--illegal or otherwise--is likely to
continue to wreak havoc on the world's marine ecosystems.